Electromagnetic waves form a family called the electromagnetic spectrum. In order, the seven groups are radio waves, microwaves, infrared, visible light, ultraviolet, x-rays and gamma rays. Visible light itself is a band of colours, running from red through to violet.
The spectrum is continuous. There are no gaps between the groups, so one blends smoothly into the next. The groups are only labels we use for different parts of the range.
Moving from radio waves towards gamma rays, the wavelength decreases and the frequency increases. Radio waves have the longest wavelength and the lowest frequency. Gamma rays have the shortest wavelength and the highest frequency.
All electromagnetic waves are transverse and they all travel at the same speed in a vacuum.
